【DFS】LeetCode 79. 单词搜索

题目链接

79. 单词搜索

思路

DFS 模板题

代码

class Solution {
    public boolean exist(char[][] board, String word) {
        int m = board.length;
        int n = board[0].length;
        boolean[][] visited = new boolean[m][n];
        for(int i = 0; i < m; i++){
            for(int j = 0; j < n; j++){
                if(dfs(board, word, 0, i, j, visited)){
                    return true;
                }
            }
        }

        return false;
    }

    private boolean dfs(char[][] board, String word, int index, int i, int j, boolean[][] visited) {
        if(index == word.length()){
            return true;
        }
        if(i < 0 || i >= board.length || j < 0 || j >= board[0].length || visited[i][j] ||
                board[i][j] != word.charAt(index)){
            return false;
        }

        visited[i][j] = true;
        boolean res =
                dfs(board, word, index + 1, i + 1, j, visited) || dfs(board, word, index + 1, i - 1, j, visited) ||
                        dfs(board, word, index + 1, i, j + 1, visited) ||
                        dfs(board, word, index + 1, i, j - 1, visited);
        visited[i][j] = false;

        return res;
    }

    public static void main(String[] args) {
        Solution solution = new Solution();
        System.out.println(solution.exist(new char[][]{{'A', 'B', 'C', 'E'}, {'S', 'F', 'C', 'S'},
                {'A', 'D', 'E', 'E'}}, "ABCCED"));
    }
}